Miniature, portable, self-powered, high speed, clinical centrifuge

ABSTRACT

A portable, miniature, self-powered, high-speed, clinical centrifuge having a housing, a motor, an energizing means, a rotor head and a rotor head cover. The energizing means for the motor is capable of being charged by a removable charger. Operation of the centrifuge rotates the rotor head at a high speed thereby separating blood cells from blood plasma within a capillary tube located within said rotor head. A timer regulates the length of time the centrifuge is in operation.

United States Patent [72] Inventors [2 l] Appl. No. [22] Filed [45]Patented [73] Assignee Marion J. Stansell;

Oskar G. Langner, San Antonio, Tex. 808,118

Mar. 18, 1969 Mar. 2, 1971 the United States of America as representedby the Secretary of Air Force [54] MINIATURE, PORTABLE, SELF POWERED,HIGH SPEED, CLINICAL CENTRIFUGE 5 Claims, 4 Drawing Figs.

[52] US. Cl 233/24, 233/26 [51] Int. Cl B04b 9/04 [50] Field of Search233/24, 26

[5 6] References Cited UNITED STATES PATENTS 7 2,783,938 3/1957 Grela etal. 233/26X 2,789,757 l/i957 Melton 233/26 3,168,473 2/1965 Goda et al..233/26 3,233,825 2/1966 Lomb 233/26 FOREIGN PATENTS 521,880 6/1940 GreatBritain 233/24 Primary Examiner--William 1. Price Attorneys-Harry A.Herbert, Jr. and Jacob N. Erlich ABSTRACT: A portable, miniature,self-powered, high-speed, clinical centrifuge having a housing, a motor,an energizing means, a rotor head and a rotor head cover. The energizingmeans for the motor is capable of being charged by a removable charger.Operation of the centrifuge rotates the rotor head at a high speedthereby separating blood cells from blood plasma within a capillary tubelocated within said rotor head. A timer regulates the length of timethe: centrifuge is in operag tion.

MINIATURE, PORTABLE, SELF POWERED, HIGH SPEED, CLINICAL CEN'IRIFUGEBACKGROUND OF THE INVENTION This invention relates generally tocentrifuges, and more particularly to a miniature, portable,hand-carried, selfpowered, high-speed clinical centrifuge capable ofperforming rapid hematocrit determinations and plasma preparation.

Blood consists of two major fractions, a fluid portion and a cellularportion. The fluid portion (plasma) is made up of proteins,carbohydrates, lipids (fats), nonprotein nitrogenous material, andsalts; the cellular portion contains erythrocytes (red blood cells),leukocytes '(white blood cells), and platelets. When blood clots, thecellular elements are included in the clot and the remaining fluid isthe serum, which differs from plasma only by the loss of fibrinogen (aprotein) utilized in the process of clotting.

Blood is a dynamic tissue, the measure of which at any given timerepresents a balance between the rate of formation and the rate ofutilization, storage, or excretion of all of its elements. The cellularelements are formed in the bone marrow and lymph nodes. They aredestroyed primarily in the spleen or elsewhere in thereticuloendothelial system of the body. In the presence of disease,these cellular elements may be destroyed at a rapid rate. The dissolvedsubstances of the plasma similarly represent a balance between theamount of materials ingested or formed in the various organs of thebody, especially the liver, and the rate of disappearance.

The volume occupied by the packed cellular elements of the blood, inrelation to the total volume, is referred to as the hematocrit. Thenormal range for men is 42-52 percent, for women 37-47 percent.Variations fromthe normal usually parallel the hemoglobin anderythrocyte values, but in pernicious anemia the hematocrit (andtherefore the color index) is disproportionate. In general, anemiasexhibit a low hematocrit value, whereas polycythemias or dehydrationreveal high values. Calculation of cellular indices is made possible byrelating the hematocrit values to the number of erythrocytes and thehemoglobin concentration. This information is of value in the diagnosisof the many types of erythrocytic disorders, particularly perniciousanemia, other macrocytic anemias, congenital hemolytic anemia, and thesecondary anemias.

l'leretofore, it was either impossible or required long, tedious andlaborious medical operations to perform rapid hematocrit determinationsand plasma preparation. The circumstances under which thesedeterminations and preparations usually had to be performed includedaeromedical evacuation operations, rugged combat zone operations,bedside operations or on flight lines and staging areas. In manyinstances, there is no external power available and there is no flatlaboratory benches available on which to place the instruments whichperform these determinations. Furthermore, the apparatus heretofore inuse for performing'hematocrit determinations and plasma preparation werecumbersome and therefore not easily lifted or carried. Thus, in manyinstances proper medical assistance could not be carried out and manylives were needlessly lost.

SUMMARY OF THE INVENTION The instant invention overcomes the problemsheretofore encountered and as set forth above. The invention is aminiabody constituents.

The centrifuge of this invention contains a series string of rechargablenickel-cadmium cells so that it can perform over separatecentrifugations before recharging, if necessary. Furthermore, thecentrifuge is equipped with a carrying handle so that it may be handcarried'during operation. The unit is also equipped with an automatictimer, a brake button for rapid deceleration, a rotor head whichaccommodates a plurality of sizes of capillary tubes, a built-in surgeresistor to prevent initial current surge and thus prolong battery lifeand motor commutator life, and its own lightweight, detachable, chargerbase which can be plugged into a variety of line voltages of varyingfrequency; The centrifuge of this invention is of high value inconducting measurements during aeromedical evacuation operations, onflight lines free of external power sources, in combat areas, inhospital wards, at the bedside, in clinical laboratories or under anyconditions where rapid hematocn't determinations are desired or whereplasma is needed immediately for chemical analysis.

The centrifuge of the instant invention is completely contained andrequires no external power source for prolonged periods. The chargerunit, by using a 6i) Hz. transformer can be used on either 60 Hz. or 400Hz. By simple circuit modification, the charger can operate on 24 to 28volts DC or on any other available power source. The centrifuge,furthermore, features a high speed (up to 18,000 r.p.m.) motor, thuspermitting especially short (30 sec.) centrifugation durations. The unitalso has a thermal surge resistor which minimizes initial current surge,thus adding greatly to battery charge life and motor commutator life. Aspring return, momentary contact, brake switch is utilized to bring thecentrifuge to a rapid stop. The brake shorts the armature winding, andthe reverse EMF creates an opposing magnetic field which brings thecentrifuge rotor to a total stop from full 'speed in approximately 12seconds. The internal nickel-cadmium cells, arranged radially about themotor can'be recharged hundreds of times and their physical arrangementlends stability to the centrifuge. The centrifuge has its own handlepermitting it to be carried while in operation and an O-ring seal islocated between its body and its hinged lid. It also has vent holesconnecting the rotor chamber to the outside thereby facilitating partialevacuation of the rotor chamber thus permitting a greater top angularvelocity. A miniature hematocrit reading scale and a simple magnifyinglens can be attached to and carried with the centrifuge of the instantinvention.

It is therefore an object of this invention to provide a miniature,clinical centrifuge which will permit rapid hematocrit determinationsand plasma preparation.

It is another object of this invention to provide a miniature, clinicalcentrifuge which eliminates the need for external power for prolongedperiods of time.

It is a further object of this invention to provide a miniature,clinical centrifuge which is readily transportable and which can beeasily lifted with one hand and carried by its own handle.

It is still another object of this invention to provide a miniature,clinical centrifuge which utilizes conventional, currently availablecomponents that lend themselves to standard massproducing manufacturingtechniques.

For a better understanding of the present invention, together with otherand further objects thereof, reference is made to the followingdescription taken in connection with the accompanying drawing and itsscope will be pointed out in the appended claims:

DESCRIPTION OF THE DRAWING FIG. 1 represents a front elevational view ofthe clinical centrifuge and charger of this invention in cross section;

FIG. 2 represents a schematic diagram of the electrical cir' cuitry ofthe clinical centrifuge and charger of this invention;

HO. 3 represents an isometric view of the clinical centrifuge of thisinvention showing the rotor head cover in its removed position; and

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3 in areduced scale.

Referring now to FIG. 1 of the drawing, numeral represents the clinicalcentrifuge of this invention about to be inserted within its charger 12.The centrifuge 10 has a housing 14 made up of cylindrical side portion16 and base portion 18. Located within housing 14 is any suitable motor20 such as a high-speed 24 volt DC motor fixedly secured to innerhousing wall 22 and motor mounting plate 23. Surrounding motor 20 is aplurality of rechargable batteries, 24, shown more clearly in FIG. 4.The batteries 24 may be of the nickel-cadmium type and are connected inseries. The total no-load voltage available from five such batteries isover 30 volts. This voltage stabilizes at near 25 volts DC duringoperation with the surge resistor shown in the circuit of FIG. 5.

Referring to FIGS. 1 and 3, a rotor head 26 is secured to the rotorshaft 28 of motor 20 by any suitable securing means such as by key 30fixedly secured to shaft 28. The rotor head 26 has a plurality ofgrooves 32 (shown clearly in FIG. 3) therein of various sizes forholding capillary tubes. The rotor head 26 further has a raised lip 34around its periphery. The lip 34 and grooves 32 are lined with a thinresilient substance 36 such as neoprene, thus obviating breakage of thecapillary tubes (not shown) placed in the rotor head grooves 32. Thegrooves 32 are of various sizes to accommodate microhematocrit capillarytubes as well as larger capillary tubes (heparinized) used to preparevolumes of plasma for chemical analysis. A rotor head cover 38 screwsonto the rotor shaft 28. The cover 38 holds the capillary tubes in placewithin grooves 32 during operation of the centrifuge 10. A knurled knob40 permits easy removal of the cover 38 when the rotor head grooves 32are to be exposed. A space 42 surrounds the rotor head 26. This space ispartially evacuated during operation through the pumping action of therotating rotor head 26. This evacuation minimizes air turbulence andpermits higher rotor speeds.

There is a layer 44 of insulatory material at the bottom and at the topof batteries 24. Upper vent holes 46 permit evacuation of the rotor headchamber 42 while bottom vent holes 48 establish continuity with theupper vent holes 46, facilitating evacuation of air through the bottomof the centrifuge 10. There is a space 50 located under motor 20 toaccommodate wire leads from charger jack 52 and the surge resistor(shown in FIG. 2). A lid 54 has a hinge 56 on one side and a lockingtypeclasp means 58 on the other side (see FIG. 3). An O-ring 60 provides atight joint between the centrifuge housing 14 and lid 54.

Referring again to FIG. 1, numeral 12 designates the nickelcadmium cellcharger. The charger 12 has a space 62 into which the centrifuge baseportion 18 fits when it is to be charged or operated from externalpower. A charger plug 64 having an insulation 66 and terminals 68 isimbedded within the charger base 69. The terminals 68 mate withterminals 70 of the charger jack 52. Appropriate polarity is assured bymeans of a projection 72 on the centrifuge base portion 18 which mateswith a slot 74 in the sidewall of charger base 69. The centrifuge 10,therefore, can be fit into the charger 12 in only one way. A space 76within the charger 12 houses an appropriate stepdown transformer anddiode rectifiers, etc.

FIG. 4 shows in more detail the position of batteries 24 within housing14 surrounding charger jack 52. The timerforming part of timer mechanism78 is located within chamber 84. The circuit diagram 86 of thecentrifuge 10 is shown clearly irTFIG. 2.

MODE OF OPERATION A blood sample is obtained by means of capillarypuncture (e.g. finger stick) or venipuncture. The heparinized capillarytube not shown is filled from one-half to three-fourths full with t eblood. he blood is moved back and forth within the tube to promotemixing with the anticoagulant. The tube is then blocked at one end witha minute piece of clay or other pliable inert material.

' The sealed tube is placed into an appropriately sized rotor headgroove 32, the rotor head cover 38 is screwed in place and the lid 54 isshut and locked. The automatic timer mechanism 78 is set for the desiredperiod of centrifugation (normally 30 seconds). While the centrifuge isoperating, it may be carried or set aside onto most any irregularsurface. After the timer switch opens, braking can be greatly increasedby depressing the red brake button 80. The brake shorts the armaturewinding, and the reverse EMF creates an opposing magnetic field whichbrings the centrifuge rotor to a total stop from full speed inapproximately 12 seconds. When the centrifuge rotor head 26 comes to acomplete stop, the lid 54 is opened, the rotor head cover 38 isunscrewed, and the capillary tube is removed. The tube is then placedonto a microhematocrit reading scale and the percent packed cell volumeis read off directly.

During storage periods, the centrifuge 10 can be conveniently placed onits charger 12 so that the ni-cad cells 24 are always in a fully chargedstate and the centrifuge 10 will be always ready for a self-poweredmission wherever it may be needed.

Although the invention has been described with reference to a particularembodiment, it will be understood to those skilled in the art that theinvention is capable of a variety of alternative embodiments within thespirit and scope of the appended claims:

We claim:

1. A miniature, portable, self-powered, high-speed clinical centrifugecomprising a housing, a motor means fixedly secured to said housing, ameans for energizing said motor means adjacent thereto, a rotor headhaving a plurality of grooves therein operably connected to said motormeans, a rotor head cover removably secured to said motor means andproximate said rotor head, a lid removably secured to said housing forcovering said rotor head and rotor head cover, said housing having abase portion, said base portion having a charger jack mounted thereinand operably connected with said energizing means, and a removablecharger having a charger plug thereon capable of being inserted withinsaid charger jack for charging said energizing means, whereby energizingof said motor means operates to rotate said rotor head at a high speedthereby separating blood cells from blood plasma within a capillary tubelocated within said grooves.

2. A miniature, portable, self-powered, high-speed clinical centrifugeas defined in claim 1 further comprising a timer mechanism within saidhousing and operably associated with said motor means for regulating theoperation thereof.

3. A miniature, portable, self-powered, high-speed clinical centrifugeas defined in claim 2 further comprising a brake within said housing andoperably associated with said motor means for quickly bringing saidrotor head to a total stop.

4. A miniature, portable, self-powered, high-speed clinical centrifugeas defined in claim 3 wherein said motor means is provided with a shaftsecured thereto, said rotor head being fixedly secured to said shaft andsaid rotor head cover being removably secured to said shaft.

5. A miniature, portable, self-powered, high-speed clinical centrifugeas defined in claim 4 wherein said rotor head further has a raised liparound its periphery, said lip and said grooves being lined with a thinresilient substance to prevent breakage of capillary tubes placedtherein.

1. A miniature, portable, self-powered, high-speed clinical centrifugecomprising a housing, a motor means fixedly secured to said housing, ameans for energizing said motor means adjacent thereto, a rotor headhaving a plurality of grooves therein operably connected to said motormeans, a rotor head cover removably secured to said motor means andproximate said rotor head, a lid removably secured to said housing forcovering said rotor head and rotor head cover, said housing having abase portion, said base portion having a charger jack mounted thereinand operably connected with said energizing means, and a removablecharger having a charger plug thereon capable of being inserted withinsaid charger jack for charging said energizing means, whereby energizingof said motor means operates to rotate said rotor head at a high speedthereby separating blood cells from blood plasma within a capillary tubelocated within said grooves.
 2. A miniature, portable, self-powered,high-speed clinical centrifuge as defined in claim 1 further comprisinga timer mechanism within said housIng and operably associated with saidmotor means for regulating the operation thereof.
 3. A miniature,portable, self-powered, high-speed clinical centrifuge as defined inclaim 2 further comprising a brake within said housing and operablyassociated with said motor means for quickly bringing said rotor head toa total stop.
 4. A miniature, portable, self-powered, high-speedclinical centrifuge as defined in claim 3 wherein said motor means isprovided with a shaft secured thereto, said rotor head being fixedlysecured to said shaft and said rotor head cover being removably securedto said shaft.
 5. A miniature, portable, self-powered, high-speedclinical centrifuge as defined in claim 4 wherein said rotor headfurther has a raised lip around its periphery, said lip and said groovesbeing lined with a thin resilient substance to prevent breakage ofcapillary tubes placed therein.